In a legend preserved by the Romantic mythologist Parthenius, Iberos is mentioned together with Keltos as offspring of Heracles by the nymph Asterope (Parthenius 30). Asterope is the daughter of Atlas. It may not be coincidence that Eber is one of the mythological ancestors of the Irish. Eratosthenes distinguished between the Spain of 500 BC, in which Celts were not so prominent a portion of the population, and that of his own time, in which they were. He was writing in the third century BC. He was criticised by Polybius and Strabo, who misunderstood the distinction which he was making. The myth is not inappropriate, for the cultural stratification of the Iberian peninsula in antiquity is complex, and it is not easy to identify traits which belong to the various components of the population. Yet the Celtiberes or Celtiberi seem to have been a blend of Celts with a previous population of Iberians. The Celtiberians were the most belligerent of the Iberian peninsula’s inhabitants and they inflicted terrible losses on the Romans in the course of their long struggle against Rome.
After the second Punic War during which Rome had perforce become a major power in Spain, the confederations of the Lusitani and Celtiberians were a constant source of trouble and expenditure to the Republic. The persistence in hostility to Rome of these groups in the period after the Hannibalic war can be considered as the military factor which more than any other brought about the transformation of the Roman army from citizen levies into a professional fighting force (Toynbee 1965:2.61).
The Celtiberians had a distinct ethnic character in the ancient world. There was a strong Celtic element in them. Other tribes, such as the Lusitani and Vaccaei, seem to have been of Celtic or part-Celtic culture and speech. Some of the Lusitani appear to